1. Field of the Invention
This invention is in the field of heat exchangers for the thermal treatment of finely divided, moist materials which involve providing at least two cyclone separators and employing a venturi-type constriction in the feeding means to the lower of the two cyclone separators to improve the thermal efficiency of the unit.
2. Description of the Prior Art
Heat exchangers for the thermal treatment of finely divided materials usually include a rotary kiln to which there is connected a series of cyclone separators. In such thermal treatment, the material charged frequently includes lumps which are so heavy that they are not taken along with the hot gases flowing upwardly in the system but instead drop downwardly against the gas flow and ultimately settle into a cyclone separator. When this happens, not only does the cyclone separator have undesired formations of inclusions and clogging of the discharge area, but the insufficiently thermally heat treated raw materials may contaminate the resulting end product.